I reached out to Service Now support and received the following response:
Reason and Proposed Solution:
The app is Geneva compatible only, meaning the developers have not yet implemented compatibility with the Helsinki release.
I put your instance name '#########' into the validator on the download link in the Store for the RingCentral app and received the following warning:
'Warning: This instance is not compatible with the app. We recommend installation only on compatible instances.'
They may make it compatible in future. Your best chance to find out would probably be through contacting the RingCentral support contact number: +1 888-898-4591.
They may know or could potentially find out who is developing the app.
Thus I am reaching out to see if the app can be made compatible with the Helsinki and any other versions of Service Now which may be coming out.